Simultaneous nutrient removal and biomass/lipid production by Chlorella sp in seafood processing wastewater

Microalgae cultivation in wastewater has received increasing attention in recent years due to its many advantages. In this work, microalgae were cultured in seafood processing wastewater (SPW) for algal biomass and lipid production as well as nutrient removal. The biomass yield of Chlorella sp. achieved in the batch cultivation was 896 mg L-1, indicating that SPWcontains a certain amount of nutrients which can be used for the growth of microalgae. However, the maximum specific growth rate of Chlorella sp. cultured in SPWthroughout the whole cultivation period was only 0.040 d(-1), suggesting that the growth of algal cells was inhibited during the culture process. High concentration of unionized ammonia in the SPWwas found to be a factor inhibiting the growth of Chlorella sp. Aerated SPW(ASPW) and diluted SPW(DSPW) proved to be better culturemedia than SPWwithout pretreatment. The maximumspecific growthratesof Chlorella sp. cultured in ASPWand DSPWduring the culture interval were 0.156 and 0.091 d(-1), respectively. Aeration pretreatment of SPW reduced the amount of toxic unionized ammonia, whilemost of the nutrientswere retained in thewastewater. Therefore, higher biomass productivity (77.7 mg L-1 d(-1)) and higher lipid productivity (20.4 mg L-1 d(-1`)) of microalgae were achieved in ASPW. Additionally, improved nutrient removal rates from ASPWwere also achieved due to the faster growth of microalgae. The average nutrient removal rates in ASPW during the whole cultivation period were 4.98 and 1.91 mg L-1 d(-1) for nitrogen and phosphorus, respectively. (c) 2018 Elsevier B.V. All rights reserved.